Pavement Quality Concrete (PQC) of M40 grade forms the structural load-bearing layer in rigid pavements of National Highways. This guide provides a detailed overview of materials, mixing, placement, curing, joint detailing, dowel and tie bar installation, and quality assurance/quality control (QA/QC) procedures. It also highlights common issues, their solutions, and aligns with MoRTH Section 602 and IRC standards. For more insights, see the main pillar page on Rigid Pavement Components.
| S. No. | Document Description |
|---|---|
| 1 | Contract Agreement |
| 2 | IRC: SP: 84-2014 |
| 3 | Ministry of Road Transport & Highways Specifications (MoRTH – 5th Revision) |
| 4 | Relevant Drawings |
PQC is a high-strength concrete layer designed to transfer traffic loads directly to the subgrade through slab action. It is especially suited for highways with heavy traffic, high axle loads, and long-term durability requirements.
Benefits of PQC include:
The Contractor shall indicate to the AE the source of all materials to be used in the concrete work with relevant test data sufficiently in advance.
Any of the following types of cement capable of achieving the design strength may be used:
| S. No. | Type of Cement | Conforming To |
|---|---|---|
| 1 | OPC 43 / OPC 53 Grade | IS:269 |
| 2 | Portland Slag Cement | IS:455 |
| 3 | Portland Pozzolana Cement | IS:1489 (Part-I) |
Admixtures conforming to IS:9103 and IS:6925 shall be permitted to improve workability of concrete or extension of setting time, on satisfactory evidence that they will not have any adverse effect on the properties of concrete with respect to strength, volume change, durability and shall have no deleterious effect on steel bars.
Fly ash up to 20% by weight of cementitious material may be used in Ordinary Portland Cement 43 or 53 Grade as part replacement of cement provided uniform blending with cement is ensured. The fly ash shall conform to IS:3812 (Part-I) and GGBFS shall conform to IRC:15-2017 / IS:16714-2018.
Site mixing of fly ash shall be permitted ensuring availability of equipment at site for uniform blending through specific mechanized facilities with automated process control like batch mix plants conforming to IS:4925 and IS:4926.
Aggregates for pavement concrete shall be natural material complying with IS:383 but with Los Angeles Abrasion Test value not exceeding 35 percent. The limits of deleterious materials shall not exceed the requirements set out in Table 600-2 of MoRTH Specifications.
The maximum size of coarse aggregate shall not exceed 31.5 mm for pavement concrete. The Los Angeles Abrasion Value shall not exceed 35. The combined flakiness and elongation index of aggregate shall not be more than 35 percent.
The fine aggregate shall consist of clean natural sand or crushed stone sand or a combination of the two and shall conform to IS:383. The fine aggregates shall have a sand equivalent value of not less than 50 when tested in accordance with IS:2720 (Part-37).
The combined gradation of fine and coarse aggregates shall be as per Table 600-3 of MoRTH Specifications.
Water used for mixing and curing of concrete shall be clean and free from injurious amounts of oil, salt, acid, vegetable matter and other substances harmful to the finished concrete.
Steel shall conform to the requirements of IS:432 and IS:1786 as relevant.
Synthetic joint filler board for expansion joints shall be used only at abutting structures like bridges and shall be of 20–25 mm thickness with a tolerance of ±1.5 mm and of firm compressible material complying with IS:1838, having compressibility more than 25%.
The joint sealing compound shall be of hot poured elastomeric type or cold polysulphide/polyurethane/silicone type having flexibility, resistance to age hardening and durability as per IRC:57.
The pre-formed sealing material shall be vulcanized elastomeric compound using polychloroprene (Neoprene) as the base polymer.
All materials shall be stored in accordance with the provisions of Clause 1014 of MoRTH Specifications.
The quantity of cement shall not be less than 360 kg/cu.m for all types of cement.
In case Fly Ash Grade-I (as per IS:3812) is blended at site as part replacement of cement, the quantity of fly ash shall be up to 20% by weight of cementitious material and the quantity of OPC in such blend shall not be less than 310 kg/cu.m.
If GGBFS is used, minimum OPC content shall not be less than 310 kg/cu.m.
The characteristic flexural strength of concrete for 28 days shall not be less than 4.5 MPa unless specified otherwise.
Target mean flexural strength for mix design shall be:
4.5 MPa + 1.65s
Where “s” is the standard deviation of flexural strength derived by conducting tests on minimum 30 beams.
The water content shall be the minimum required to provide the agreed workability for full compaction of concrete to the required density as determined by trial mixes.
The maximum free water cement ratio shall be:
IRC:44 shall also be referred regarding selection of water-cement ratio.
The ratio between the 7-day and 28-day strength shall be established for the mix to be used in the slab in advance by testing pairs of beams and cubes at each stage on at least six batches of trial mix.
The average strength of 7-day cured specimens shall be divided by the average strength of 28-day specimens for each batch and the ratio “R” shall be determined and expressed to three decimal places.
The workability of concrete at the point of placing shall be adequate for the concrete to be fully compacted and finished without undue flow.
The optimum workability suitable for the paving plant being used shall be determined by the Contractor and approved by the AE.
The workability shall be established for the type of paving equipment available.
A slump value in the range of 25 ± 15 mm is considered suitable for paving works, however this may be modified depending upon site requirements and reviewed by the AE.
Laboratory trials of design mix shall be carried out with materials from approved sources as per IRC:44.
Trial mixes shall be made in presence of the AE and the design mix shall be subject to review and approval by the AE.
The cement concrete pavement shall be laid over DLC sub-base constructed in accordance with relevant drawings and specifications.
It shall be ensured that the DLC sub-base is not damaged before laying the concrete pavement.
If DLC is found damaged at certain locations or cracks wider than 10 mm are observed, repairs shall be carried out using:
before laying the separation membrane layer.
A separation membrane shall be used between PQC and DLC sub-base.
The separation membrane shall consist of impermeable PVC sheet of 125 micron thickness, transparent or white in colour, laid flat with minimum creases.
Before placing the separation membrane, the DLC surface shall be swept clean using an air compressor to remove all extraneous materials.
Where overlap of plastic sheets is necessary, the overlap shall be at least 300 mm.
Any damaged sheathing shall be replaced.
The separation membrane may be nailed to the lower layer using concrete nails.
The separation membrane may be omitted when two layers of wax-based curing compound are used.
Tie bars shall be provided at longitudinal joints as per dimensions and spacing shown in drawings and in accordance with Clause 602.6.6 of MoRTH Specifications.
At curves, tie bars shall be placed radially in the direction of radius.
The work shall be carried out in accordance with Clause 602.6.5 of MoRTH Specifications.
Dowel bars shall:
Unless specified otherwise, dowel bars shall be positioned at mid-depth of slab within a tolerance of ±20 mm and centered equally about intended joint line within ±25 mm.
For all bars inserted after laying of slab except those inserted by Dowel Bar Inserter, the alignment tolerance may be twice that specified above.
The deflection of top edge of filler board shall not exceed 13 mm when subjected to a load of 1.3 kN.
Residual deflection after removal of load shall not exceed 3 mm.
Fixings for joint assembly shall not fail under 1.3 kN load and shall fail before load reaches 2.6 kN.
Fixings shall be considered failed if displacement exceeds 3 mm under test load.
Dowel bars in contraction joints, construction joints and expansion joints shall be covered by thin plastic sheath.
The sheath thickness shall not exceed 0.5 mm and shall be tightly fitted:
The locations and type of joints shall be as shown in the drawings. Joints shall be constructed depending upon their functional requirements.
The location of joints shall be transferred accurately at site and mechanical saw cutting of joints shall be carried out as per stipulated dimensions.
It shall be ensured that the required depth of cut is achieved from edge-to-edge of the pavement.
Transverse and longitudinal joints in PQC and DLC shall be staggered so that they are not vertically coincident and shall be spaced:
Sawing of joints shall be carried out using diamond studded blades soon after concrete has hardened sufficiently to take the load of the sawing machine and crew members without damaging the pavement texture.
Sawing operation may commence as early as 4–8 hours after laying of concrete pavement but not later than 8–12 hours, depending upon ambient temperature, wind velocity, relative humidity and maturity of concrete.
Where kerb is cast integrally with the pavement slab, joint cutting shall also be extended to the kerb.
Transverse joints shall be contraction joints, construction joints and expansion joints constructed at spacing shown in the drawings.
Transverse joints shall be straight within the following tolerances:
Deviation of preformed filler board (IS:1838) from intended line of joint shall not exceed ±10 mm.
The best fit straight line through joint grooves as constructed shall not be more than 25 mm away from intended joint line.
Deviation of joint groove from best fit straight line shall not exceed 10 mm.
Transverse joints on each side of longitudinal joint shall:
All transverse joints shall have sealing grooves sealed in accordance with Clause 602.10 of MoRTH Specifications.
Contraction joints shall be placed transversely at predetermined locations as per drawings/design using dowel bars.
These joints shall be cut after initial hardening of concrete when the slab is capable of supporting the load of joint sawing machine without causing damage.
Contraction joints shall consist of:
Expansion joints shall consist of:
The filler board shall be positioned vertically with prefabricated joint assemblies along the joint line within permissible tolerances specified in Clause 602.6.2.1.
Adjacent slabs shall be completely separated from each other by the joint filler board.
Transverse construction joints shall be provided whenever concreting:
These joints shall be located at contraction joint locations and provided with dowel bars.
If sufficient concrete has not been mixed to extend up to the next contraction joint and interruption occurs, the concrete placed shall be removed up to the previous joint and disposed of.
Longitudinal joints shall be constructed either by forming or by sawing as detailed in the drawings.
Sawed longitudinal joints shall be provided when pavement placement width exceeds 4.5 m.
The groove may be cut after final setting of concrete.
Longitudinal joints shall be sawn to at least:
One-third depth of slab ±5 mm
or as indicated in the drawings.
Concreting should preferably be avoided during the rainy season. However, when concrete is being placed during monsoon months and rain is anticipated, sufficient tarpaulin sheets or other waterproof coverings shall be kept ready along the line of work.
Whenever rainfall occurs, all freshly laid concrete which has not yet been covered for curing purposes shall be adequately protected.
Any concrete damaged due to rain shall be removed and replaced at the Contractor’s cost.
No concreting shall be carried out when the temperature of concrete reaching the paving site exceeds 30°C.
Under adverse environmental conditions such as:
temporary tents mounted on mobile trusses may be provided over the freshly laid concrete for a minimum period of 3 hours or as directed by the AE.
To reduce concrete temperature, chilled water or ice flakes may be used wherever necessary.
When ambient temperature exceeds 35°C, concreting shall not be permitted.
Side forms and rails shall be provided for fixed form paving works.
All side forms shall be fabricated from mild steel having depth equal to the pavement thickness or slightly less to accommodate irregularities in the sub-base.
Forms may be placed over steel packing plates or shims to compensate for unevenness of sub-base.
Forms and rails shall be securely fixed using not less than 3 stakes/pins for every 3 m length to prevent movement in any direction.
Forms and rails shall satisfy the following tolerances:
The forms shall be bedded on a continuous layer of low moisture content lean cement mortar or concrete and set to the required line and levels shown in drawings within the following tolerances:
Sufficient forms shall always be available and aligned for at least:
whichever is more.
Where slip form paving is adopted, guidewires shall be provided along both sides of the slab.
Each guidewire shall be maintained at a constant height above and parallel to the required pavement edge within a vertical tolerance of:
±3 mm
Additionally, one guidewire shall be maintained at a constant horizontal distance from the pavement edge within a lateral tolerance of:
±10 mm
Guidewires shall be supported on stakes spaced at 5 m to 6 m intervals using connectors capable of fine horizontal and vertical adjustments.
The guidewire shall be tensioned in such a manner that a 500 gm suspended load produces a deflection not exceeding 20 mm at midpoint between stakes.
Ends of guidewires shall be anchored to fixed points or winches and not directly to stakes.
On curves, stake spacing shall not exceed:
3 m Centre-to-Centre
The stakes shall be properly fixed into ground and connectors maintained at correct alignment and level from:
A systems approach may be adopted for construction of concrete pavement.
The Contractor shall submit a detailed Method Statement for approval of the AE prior to commencement of work. The Method Statement shall include:
The capacity of paving equipment, batching plant and ancillary equipment shall be adequate to achieve a paving rate of at least:
500 m per day
The paving speed of slip form paver shall not be less than:
1.0 m per minute
Concreting operations shall proceed continuously without unnecessary stoppages or interruptions.
Batching and mixing of concrete shall be carried out at a centralized batching and mixing plant equipped with automatic controls.
The batching plant shall be located at a suitable approved location considering:
The location shall be selected considering the properties of concrete mix and available transportation arrangements.
All materials shall be proportioned by weight at the batching plant, with each material weighed separately.
Where properly graded aggregate of uniform quality cannot be maintained, aggregate grading shall be controlled through appropriate blending techniques.
The batching plant shall consist of:
Weighing hoppers shall be sealed and vented to prevent dust emission.
The plant shall be equipped with a suitable non-resettable batch counter to indicate the number of batches proportioned.
Continuous type mixing plants may also be used provided electronic sensors are installed for weighing ingredients before feeding.
The batching plant shall proportion aggregates and cement through automatic weighing devices using load cells.
Mixers shall be:
Mixers shall thoroughly combine aggregates, cement and water into a homogeneous mix within the specified mixing time.
Each stationary mixer shall have an approved timing device which:
Mixer blades shall be repaired or replaced when worn by 20 mm or more.
The Contractor shall maintain:
An air-conditioned centralized computer control cabin shall be provided for automatic operation of batching plant equipment.
The batching plant shall be designed for quick shifting from one location to another whenever required.
Concrete shall be laid using approved fixed form or slip form paving equipment designed to:
All operations shall be completed in a single pass of the paving machine with minimum hand finishing.
The paving equipment shall produce dense and homogeneous concrete pavement conforming to drawings and specifications.
Internal vibrators shall operate at:
8000 – 10000 impulses per minute
under load with maximum vibrator spacing of:
600 mm
Variable vibration settings shall be available in the paving machine.
The Contractor shall provide adequate number of concrete saw machines with sufficient diamond-edge saw blades.
The saw machine may be:
Water tanks with flexible hose and pumping arrangement shall be made available on priority for saw cutting operations.
Freshly mixed concrete shall be transported from the batching plant to paving site using tipping trucks or transit mixers of approved capacity and design.
Sufficient number of transport vehicles shall be deployed to ensure continuous supply of concrete.
Concrete shall be protected against weather using covers during transportation.
During loading, trucks shall be moved back and forth under discharge chute to prevent segregation.
Transport vehicles shall maintain concrete in homogeneous condition without segregation or loss of cement slurry.
The total time from addition of water to completion of surface finishing and texturing shall not exceed:
| Concrete Temperature | Maximum Time Limit |
|---|---|
| Less than 25°C | 120 Minutes |
| 25°C to 30°C | 90 Minutes |
Concrete placement in front of PQC paver should preferably be carried out using side placers to avoid damage to DLC by concrete trucks.
Where unavoidable, movement of concrete trucks over DLC may be permitted only with approval of the Engineer.
The paver shall be capable of laying the full carriageway width in a single pass and lift.
For fixed form paving, forms shall be installed in advance as per Clause 602.8.
Prior to paving, the site shall be inspected by the AE to verify:
Concrete placement shall progress only at a rate that permits proper:
While concrete remains plastic, surface texturing shall be carried out using brushes or tines in accordance with Clause 602.9.11 and as directed by the AE.
The slab surface and edges shall be cured using sprayed liquid curing membrane complying with Clause 602.9.12.
After texturing and before application of curing compound, chainage marks shall be embossed on concrete surface at every:
100 m interval
The slip form paving train shall consist of a power operated machine capable of spreading, compacting and finishing concrete in one continuous operation.
The slip form paver shall compact concrete using internal vibrators and shape the slab using:
Concrete shall be deposited uniformly across full paving width without segregation and at all times in excess of the required surcharge level.
Concrete shall be struck off to required average and differential surcharge using:
The strike-off equipment shall be capable of rapid adjustment for:
The level of conforming plate and finishing beams shall be controlled automatically from guide wires installed as per Clause 602.8 using sensors attached at four corners of the paver.
Paver alignment shall be automatically controlled from guide wire through at least one set of sensors attached to the paving machine.
Alignment and level of ancillary machines used for finishing, texturing and curing shall also be automatically controlled relative to guide wires or slab surface and edge.
Slip-form paving machines shall be equipped with vibrators having variable output and a maximum energy output of not less than:
2.5 KW per metre width of slab per 300 mm depth of slab
for paving speeds up to:
1.5 m per minute
The machine shall possess sufficient mass to provide adequate reaction during spreading and paving operations and maintain continuous forward movement under all working conditions.
Normal paving speed shall conform to Clause 602.9.1 of MoRTH Specifications.
Slip-form pavers having sufficient width to pave the full carriageway in a single pass shall generally be used unless otherwise specified in the Contract.
Where full-width paving is not feasible, part-width paving may be permitted by the Engineer under unavoidable circumstances.
In case of part-width paving:
Upon instructions of the Engineer, the Contractor shall scrape the plastic concrete surface using a tube float before texturing.
The tube float shall consist of:
The tube float length shall preferably exceed half the slab length (i.e. half the distance between two transverse contraction joints).
The tube float shall be placed at the centre of slab up to longitudinal joint and pulled slowly and uniformly towards slab edges.
The float tube shall be cleaned frequently and removed slurry shall be discarded.
The fixed form paving train shall consist of separate power-operated machines for spreading, compacting and finishing concrete in one continuous operation.
Concrete shall be discharged without segregation into a hopper spreader equipped with controls for regulating deposition over the sub-base.
The spreader shall strike off concrete to a level requiring only minor cutting down by the distributor.
The distributor shall further strike off concrete to adequate surcharge level to ensure complete compaction by the vibratory compactor.
Hand-guided methods of construction shall be permitted only in restricted areas and short lengths where mechanized construction becomes unavoidable.
Such works shall be carried out only after obtaining prior written approval from the AE.
At interfaces between rigid and flexible pavements, a reinforced buried transition slab of minimum:
3 m length
shall be provided to ensure durable and smooth transition at the junction.
The details of transition slab shall conform to IRC:15.
After final floating and finishing of slab and before application of curing compound, the concrete surface shall be textured either:
Texturing shall be carried out by tining using rectangular steel tines.
A beam or bridge mounted with steel tines shall be provided with automatic sensing and control devices linked with the paver or auxiliary equipment.
Alternatively, brush texturing may be carried out if instructed by the AE.
The brushed texture shall be applied uniformly across the slab using wire brushes having minimum width:
450 mm
However, wider brushes of approximately:
3 m length
are preferred.
Brushes shall consist of:
The brush shall contain two rows of tufts spaced:
20 mm apart
The tufts in one row shall be aligned opposite the gaps in the other row.
Brushes shall be replaced when the shortest tuft length reduces to:
90 mm
Immediately after surface texturing, the surface and sides of slab shall be cured using approved resin-based aluminized reflective curing compound applied by mechanical sprayer.
The curing compound shall:
All joints shall be sealed using approved sealants conforming to Clause 602.2.10 and shall be applied in accordance with Clause 602.10 of MoRTH Specifications.
The subgrade forms the foundation of rigid pavements, and proper preparation is essential for long-term PQC performance.
Figure 3: DLC Placement & Compaction
| Test | Standard | Frequency | Requirement |
|---|---|---|---|
| Normal Consistency | IS 4031 | Each batch | As per IS 12269 / IS 8112 / IS 1489 |
| Initial & Final Setting Time | IS 4031 | Each batch | Initial ≥ 30 min, Final ≤ 600 min |
| Soundness | IS 4031 | Each batch | Max 10 mm |
| Compressive Strength | IS 4031 | Each batch | 28-day strength as per grade |
| Chemical Test | IS 4031 | Every 6 months | As per IS codes |
| Test | Standard | Frequency | Requirement |
|---|---|---|---|
| pH Value | IS 3025 | Every 3 months | ≥ 6 |
| Organic Impurities | IS 3025 | Every 3 months | Max 200 mg/l |
| Inorganic | IS 3025 | Every 3 months | Max 3000 mg/l |
| Sulphate | IS 3025 | Every 3 months | Max 400 mg/l |
| Chlorides | IS 3025 | Every 3 months | Max 500 mg/l |
| Suspended Matter | IS 3025 | Every 3 months | Max 2000 mg/l |
| Test | Standard | Frequency | Requirement |
|---|---|---|---|
| Sieve Analysis | IS 383 / IS 2386 | 1/day | As per grading table |
| Aggregate Impact | IS 2386 | 1/week | Max 45% (30% for wearing surface) |
| Los Angeles Abrasion | IS 2386 | As required | Max 35% |
| Alkali Reactivity | IS 2386 | Once/source | Innocuous |
| Soundness | IS 2386 | Once/source | 12% Na₂SO₄ / 18% MgSO₄ |
| Flakiness & Elongation | IS 2386 | Weekly | Max 35% |
| Water Absorption | IS 2386 | Once/source | Max 2% |
| Test | Standard | Frequency | Requirement |
|---|---|---|---|
| Sieve Analysis | IS 383 | Daily | As per Zone I/II/III |
| Silt Content | IS 2386 | Daily | Max 3% |
| Fineness Modulus | IS 383 | Daily | 2 – 3.5 |
| Sand Equivalent | IS 2386 | Once/source | ≥ 50% |
| Test | Standard | Frequency | Requirement |
|---|---|---|---|
| Slump Test | IS 1199 | Each transit mix | As per mix design |
| Surface Regularity | IRC SP-16 | As required | 3 mm |
| Surface Level Tolerance | MORTH | Every 10 m | ±5 mm |
| Strength of Concrete | IS 516 | 2 cubes + 2 beams / 150 m³ | As per mix design |
Standard construction methodologies for highway works as per MoRTH 5th Revision and IRC Specifications.
